Early in “Americanah,” Chimamanda Ngozi Adichie's first novel in seven years, a newly arrived Nigerian college student and her Nigerian aunt are chatting in the aunt's Brooklyn apartment.

Explaining why she'll straighten her hair for upcoming interviews, Aunty Uju gets right to the point: “You are in a country that is not your own. You do what you have to do if you want to succeed.”

Ifemelu will learn this for herself in the years to come — even as she resists the pull of a country where people continually “smooth all the scalloped surfaces.”

“Americanah” spends many early pages retracing Ifemelu's Nigerian childhood, returning to Nigeria at journey's end; these sections revolve around the on-again, off-again relationship between Ifemelu and Obinze, her teenage love from Nigeria. We also spend a promising but underdeveloped section with Obinze in England, from which he is eventually deported as an illegal immigrant.

But the heart of Adichie's book lies elsewhere, within the country folded into its title — the word Nigerians use for those compatriots who have been to the States and never fully return home.

In America, a woman who “had spoken English all her life” will consciously develop an American accent so that she can be understood. Strapped for cash, she'll take on degrading jobs she'd never imagined doing. To land one job, she'll use relaxer and straighten her naturally kinky hair.

But during her 13 years in America — arriving like Adichie, author of “Half a Yellow Sun,” in 1996 and returning to Nigeria in 2009 — Ifemelu never quite fits in. She learns to speak like an American, but “her triumph was full of air ... because she had taken on, for too long, a pitch of voice and way of being that was not hers.”

That outsider status sharpens Ifemeulu's senses, and it's her keen observations of American life — many of them captured in the blog through which she earns her living — that are what's best in this book.

Ifemelu dissects American slang. The meaning of Obama. Slovenly American dress, reflective of an easy sense of superiority. American's overly indulgent, self-absorbed child-rearing. The petty infighting among academics. The herd mentality among the upwardly mobile.

And, most of all, Americans' screwed-up language and politics of race.

It's as though Adichie is caught between her halfhearted investment in a traditional narrative and something truly different like Jean Toomer's "Cane" (1923) — a novel we watch Ifemelu read and which, with its disparate vignettes and mixed styles, offers a sweeping, multidimensioned panorama of black American life.

But despite this novel's identity crisis, Adichie's willingness to try something different — and her insistence on posing questions that matter — is bracing. Discussing race, this novel takes real risks — and challenges us to do the same with each other.